Antibiotics May Reduce Biologic Therapy Persistence in Psoriasis

Patients with psoriasis who receive antibiotics may be more likely to discontinue their biologic therapy, a new study suggests.¹ In this French cohort study, the effect increased with multiple antibiotic courses, suggesting that gut microbiota alterations may play a role in reducing biologic persistence.

This retrospective cohort study is published in JAMA Dermatology.

“In this cohort study, antibiotic exposure was significantly associated with an increased risk of discontinuation of biologic therapies in psoriasis,” wrote the researchers of the study. “These findings support the hypothesis that antibiotics, potentially through gut dysbiosis, may reduce biologic persistence. However, unmeasured confounders limit causal interpretation. Further studies are necessary to validate these findings.”

Biologic therapies have transformed the treatment of psoriasis and other skin conditions, but their effectiveness can decline over time due to real-world factors.² Loss of efficacy may result from the development of anti-drug antibodies, dosing gaps, or differences between loading and maintenance doses. Some medications, such as tumor necrosis factor inhibitors, are more prone to neutralizing antibody effects, whereas others, like certain anti-interleukins, are less affected. Understanding these factors is crucial for dermatologists to optimize long-term treatment outcomes, guide dosing strategies, and anticipate potential decreases in drug response.

The study used data from the French National Health Insurance database between June 2011 and December 2022.¹ Adults initiating biologic therapy for psoriasis were included, excluding patients with preexisting inflammatory bowel disease. Antibiotic exposure was assessed both at baseline—categorized as none, 1, or 2 or more dispensations in the 6 months before biologic initiation—and as a time-dependent variable during follow-up, reflecting dispensations in the 6 months prior to each assessment.

The primary outcome was discontinuation or switching of the initial biologic therapy.

Among 36,129 patients included in the study (42.0% female; mean [SD] age, 48.4 [15.1] years), 9366 (25.9%) were exposed to antibiotics at baseline, and 21,900 (60.6%) received antibiotics during follow-up. The most commonly prescribed classes were β-lactams, macrolides, and fluoroquinolones. Antibiotic exposure was associated with a higher risk of biologic discontinuation (HR, 1.12; 95% CI, 1.08-1.16). The risk increased with multiple antibiotic dispensations, showing a dose-response relationship (weighted HR, 1.29; 95% CI, 1.24-1.35). These findings suggest that antibiotic use may reduce the long-term persistence of biologic therapies in patients with psoriasis.

However, the researchers acknowledged some limitations to the study. Information on reasons for biologic discontinuation and patient adherence was unavailable, and residual confounding from lifestyle factors or comorbidities cannot be ruled out. These limitations may influence the interpretation of the observed association between antibiotic use and reduced biologic persistence.

Despite these limitations, the researchers believe the study finds antibiotic exposure was associated with an increased risk of discontinuing biologic therapy, with stronger effects seen after multiple courses. These findings support the hypothesis that antibiotics—potentially through gut microbiota alterations—may reduce biologic persistence.

“Clinically, these findings underscore the importance of careful antibiotic prescribing in patients receiving biologics,” wrote the researchers. “While causality is unproven, minimizing unnecessary antibiotic exposure may support better treatment persistence. Further research is warranted to confirm these associations, clarify underlying mechanisms, and identify patient-related and treatment-related factors influencing biologic durability.”

References

1. Ouakrat R, Penso L, Jullien D, et al. Antibiotic use and the persistence of biologic therapies in patients with psoriasis. JAMA Dermatol. Published online November 12, 2025. doi:10.1001/jamadermatol.2025.4427

2. Palmer WJ. Real-world factors that affect the efficacy of biologics. Dermatology Times®. April 22, 2019. Accessed November 24, 2025. https://www.dermatologytimes.com/view/real-world-factors-affect-efficacy-biologics